EUVD-2026-9835

Comprehensive Technical Analysis of EUVD-2026-9835

1. Vulnerability Assessment and Severity Evaluation

The vulnerability EUVD-2026-9835, also known as CVE-2026-30790, pertains to an "Improper Restriction of Excessive Authentication Attempts" and "Use of Password Hash With Insufficient Computational Effort" in RustDesk Server Pro and RustDesk Server (OSS). This vulnerability allows for password brute-forcing attacks, which can compromise user authentication mechanisms.

Severity Evaluation:

• Base Score: 9.3 (Critical)
• Base Score Version: 4.0
• Base Score Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

The high base score indicates a critical vulnerability due to the ease of exploitation (low attack complexity) and the significant impact on confidentiality and integrity.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Network-Based Attacks: Since the vulnerability affects network-accessible authentication mechanisms, attackers can exploit it remotely.
• Brute Force Attacks: The primary exploitation method involves brute-forcing passwords due to insufficient computational effort in password hashing and lack of rate limiting on authentication attempts.

Exploitation Methods:

• Password Brute Forcing: Attackers can systematically attempt multiple passwords until the correct one is found. The use of weak hashing algorithms (SHA256(SHA256(pwd+salt)+challenge)) and lack of rate limiting make this feasible.
• Automated Scripts: Attackers can use automated scripts to perform rapid, repeated authentication attempts, increasing the likelihood of successful brute-forcing.

3. Affected Systems and Software Versions

Affected Software:

• RustDesk Server Pro: Versions through 1.7.5
• RustDesk Server (OSS): Versions through 1.1.15

Platforms:

• Windows
• MacOS
• Linux

Modules:

• Peer authentication
• API login modules

4. Recommended Mitigation Strategies

Immediate Mitigations:

• Rate Limiting: Implement rate limiting on authentication attempts to prevent brute-force attacks.
• Stronger Hashing Algorithms: Use stronger, more computationally intensive hashing algorithms such as bcrypt, scrypt, or Argon2.
• Multi-Factor Authentication (MFA): Enforce MFA to add an additional layer of security.

Long-Term Mitigations:

• Regular Updates: Ensure that all systems are updated to the latest patched versions.
• Security Audits: Conduct regular security audits and penetration testing to identify and mitigate similar vulnerabilities.
• User Education: Educate users on the importance of strong, unique passwords and the risks associated with weak passwords.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to organizations and individuals using RustDesk Server Pro and RustDesk Server (OSS) within the European Union. The potential for unauthorized access to sensitive information and systems can lead to data breaches, financial losses, and reputational damage. Given the critical nature of the vulnerability, it underscores the need for robust cybersecurity measures and compliance with regulations such as GDPR.

6. Technical Details for Security Professionals

Vulnerable Code:

• File: src/server/connection.Rs
• Routines: Salt/challenge generation, SHA256(SHA256(pwd+salt)+challenge) verification

Technical Recommendations:

• Code Review: Conduct a thorough code review of the authentication mechanisms to identify and rectify weak hashing algorithms and lack of rate limiting.
• Patch Management: Ensure that patches and updates are applied promptly to mitigate known vulnerabilities.
• Monitoring and Logging: Implement robust monitoring and logging to detect and respond to suspicious authentication activities.

References:

• GitHub Repository
• NVD Detail

Assigner: VULSec

EPSS: N/A

ENISA ID Product:

• RustDesk Server Pro: Versions 0 ≤ 1.7.5
• RustDesk Server (OSS): Versions 0 ≤ 1.1.15

ENISA ID Vendor:

• rustdesk-server-pro
• rustdesk-server

By addressing these vulnerabilities promptly and comprehensively, organizations can significantly reduce the risk of exploitation and enhance their overall cybersecurity posture.